[R] survit function and cox model with frailty
gc4 at duke.edu
Tue May 20 03:55:06 CEST 2003
I have followed through Thomas' suggestions, but unfortunately, to no
avail. I added a statement identifying the id group variable to the temp
data frame which I feed into the survfit function.
temp <- data.frame(t0=c(0,365,730,1095,1460),
However, I obtain the following error message:
fit2 <- survfit(model1, newdata=temp, individual=TRUE)
Error in x2 %*% coef : non-conformable arguments
The survfit function seems to be looking for a coefficient for the frailty
term, which, of course, is not there given that:
h(t)=h0(t)*a*exp(Xb), where a is the frailty term.
I also tried to add a "frail(id)"=c(1,1,1,1,1) line to the statement
that creates the temp data frame. But, again, I obtain the following error
> fit2 <- survfit(model3, newdata=temp, individual=TRUE)
Error in model.frame(formula, rownames, variables, varnames, extras,
variable lengths differ
Thank you very much for any suggestions. Thanks, in particular, to Thomas.
On Mon, 19 May 2003, Thomas W Blackwell wrote:
> Giacomo -
> Here's just a guess, since I have no experience with this.
> Try adding a sixth variable to the data frame "temp", a
> variable named "id" with value c(1,1,1,1,1). Maybe that
> will do it ? This is consistent with your intention in
> setting individual=TRUE, and it will give the frailty()
> term that's already in the model something to work with.
> - tom blackwell - u michigan medical school - ann arbor -
More information about the R-help